A team of astronomers has identified a comet at a distance of more than two thousand four hundred million kilometers from the Sun; no other comet on the way to the Sun has been seen at such a great distance: beyond Saturn. And, moreover, with unique characteristics never seen in a body like this.
Named K2 , the orbit of this comet indicates that it comes from the cloud of Oort , an immense and spherical region containing billions of comets.
But the most striking thing about this comet is that it has no tail, at least, that we can observe: it is not produced by the evaporation of water ice, since it is too far from the Sun, but freezes like a rock.
“Because K2 is so far from the Sun and so cold, the water ice is frozen as a rock, and we know for sure that its activity is not produced by the evaporation of the ice, as in other kites, ” according to the professor of Planetary Science and Astronomy, David Jewitt, who has led in analysis of comet observations.
Instead, substances such as nitrogen, carbon dioxide, and oxygen escape into the vacuum; even more volatile than water. That is to say: solar radiation is not strong enough to ‘release’ these substances, whose molar mass is superior to that of water.
“The volatile substances on the surface of K2 are the ones that absorb heat from the Sun, so in a sense, the comet is falling off its outer layers,” says Jewitt.
But the comet is approaching.
And in doing so, it heats up. In 2022, it will reach its closest distance from the Sun, which will be a point to orbit Mars.
“It should be more and more active when it approaches the Sun and, when this happens, it will form a queue,” says Jewitt.
The discovery allows scientists, for the first time, to monitor the activity of a comet at an extraordinarily distant distance. These are the first signs of activity ever seen in a comment that enters for the first time in the planetary zone of our Solar System.
Why do we know that it is the most primitive comet we have ever seen?
Most comets are discovered much closer to the Sun, closer to the orbit of Jupiter, so volatile gases on the surface have already been removed when scientists get to see them.
That’s why scientists are sure that it is the oldest and most distant comet ever observed on its way into the solar system.
Comet K2 is currently located beyond the orbit of Saturn, and has been traveling for millions of years from its home in the frozen outer space of the Solar System, the Oort cloud, where the temperature is about -262 degrees Celsius.
It was photographed by the NASA Hubble Space Telescope and the observations of the researchers have been published in the Astrophysical Journal Letters.
It astonishes, furthermore, that after finding K2 in the Hubble images, the researchers realized that the comet had already been photographed before. Specifically, in 2013, by the Canada-France-Hawaiian Hawaii Telescope: Man-To Hui, a graduate student at the University of California, Los Angeles, identified K2 while searching for images in a Canadian archive. But it was so weak that no one noticed its existence when the photos were analyzed.